In stereoscopic photographing that acquires a multi-viewpoint image of a subject using a plurality of imaging devices, respective lens devices of the imaging devices preferably have the same optical condition. Thus, there is known a lens system, which is configured to render control objects changing an optical condition, such as a focus, a zoom or an iris, to be associated with each other between the lens devices (see, e.g. Patent Literatures 1 and 2).
According to Patent Literature 1, the lens system is provided with a dedicated controller which is configured to link and drive the focus or zoom of two lens devices, each of the lens devices being connected to the controller. The controller is configured to transmit an operation signal to each lens device depending on the operation quantity of the focus or zoom of an operation unit provided in the controller, thus driving each lens device under the same optical condition.
In the lens system according to Patent Literature 2, two lens devices are connected to each other, so that either of the lens devices is set as a control master for every control object, such as the focus, the zoom or the iris. Further, the controller is connected to the lens device (hereinafter, referred to as a control-master lens device) which is set as the control master, thus driving the control object.
The control-master lens device is operated in response to a control signal that is input from the controller connected to the control-master lens device. Further, the control-master lens device transmits a control signal corresponding to a set value of the control object in the control-master lens device to another lens device (hereinafter, referred to as a control-slave lens device). The control-slave lens device is operated in response to a control signal that is input from the control-master lens device.
In the lens system described in Patent Literature 2, the controller utilized when each lens device is used as a stand-alone may be converted into a controller that links and drives the two lens devices in the stereoscopic photographing.